1. Field of the Invention
The present invention generally relates to a switching device that shares input/output devices through switching connections among computers, and more particularly, to a switching device that can be remote-controlled by a remote-control computer.
2. Description of the Related Art
As the processing performances of computers have greatly improved, computers are being even more widely used. For instance, an increasing number of individuals own more than one computer, to have more opportunities to use computers having different work environments from one another. In this situation, input/output devices, such as a keyboard, a display, and a mouse, are connected to the computers via a switching device, so as to save space and costs.
Such a switching device is generally called a KVM (K: Keyboard, V: Video, M: Mouse) switch. A KVM switch is connected to the input/output devices and the computers, and activates one of the connections between the input/output devices and one of the computers. A user operates the KVM switch to select which one of the computers should be connected to the input/output devices.
With such a conventional KVM switch, however, it is necessary for a user to operate the KVM switch through the mouse or the keyboard connected to the KVM switch, and the user must be at the location of the input/output devices. To solve this problem, a KVM switch that can be remote-controlled has been suggested.
With a KVM switch that can be remote-controlled, a user can have access to computers connected to the KVM switch through a PC that is located at a distance via a network, as well as through a mouse and a keyboard that are connected to the KVM switch.
When image data are transmitted from the computers connected to the KVM switch to a remote-control computer over the network, it is necessary to compress the image data, since the amount of data contained in the image data is too large. However, the image data compression degrades the image quality, though it does reduce the data amount.
Also, the mouse coordinate data are transmitted as relative coordinate value data from a remote-control computer over the network, which results in missing packets in the mouse coordinate data or delays of movement signals of the mouse due to line congestion.
Furthermore, with the conventional KVM switch, the mouse cannot function as an absolute value device, unless software such as a special-purpose driver for the mouse connected to remote-control computers over the network is installed in the computers in advance.